CD4 and COVID-19: Moreover, COVID-19 presented a robust antiviral response including higher levels of IFNG, a hallmark of CD8+ T cells activity and CD4+ T cells Th1 response, type I interferons (IFNA and IFNB) and their receptors (IFNAR1), transcriptional regulators (STAT2, IRF3, IRF7, and IRF9) and interferon-stimulated genes (OAS2, OAS3, ISG15, RNASEL, IFIT5, and RIGI) (Figure 6e).